This invention relates to plant husbandry and more particularly to a plant receptacle with in-situ means for determining the moisture content of the potting soil therein.
In the husbandry of living plants cultivated in other than a natural environment, such as in greenhouses, nurseries and private homes, it is necessary that the moisture content of the soil in which the plants are growing be maintained at an optimum level to prevent plant loss or retardation of growth. Household plants are especially susceptible to such misfortunes in that the home environment is even less compatible with a natural environment than that of a greenhouse or nursery. Amateur home horticulturists are not always aware that optimum soil moisture content varies with the plant species and are not always knowledgeable of the optimum soil moisture content for the particular plant species they wish to cultivate. Widely diseminating such knowledge, however, is not a solution to the problem unless a simple, economical device for measuring the moisture content of soil is available.
It is known that the approximate moisture content of soil may be ascertained by measuring the resistance between two spaced points in the soil and comparing the resistance measured with the resistance of similar soil having a known moisture content. One example is found in U.S. Pat. No. 2,461,111 which shows a moisture indicating apparatus having two spaced stakes, each of which has an electrode attached thereto and electrically connected to an ohmmeter. The stakes are thrust into the soil to a known depth and the soil resistance is measured and evaluated in terms of soil moisture content. This apparatus is primarily useful, however, in the cultivation of fruits and vegetables in an outdoor environment. It has also been suggested that plant moisture meters having a single probe be used by inserting the probe into the soil of a house plant. The problems encountered by the use of such a meter is that the moisture being measured at a particular point is not representative of the soil conditions across the roots of the plant. A disadvantage of using the frequency apparatus to measure the moisture content of the soil in a plant receptacle is the possbility of damaging delicate root structure when the stakes are frequently thrust into the potting soil.